Microelectronic devices, stacked microelectronic devices, and methods for manufacturing such devices

ABSTRACT

Stacked microelectronic devices and methods for manufacturing such devices are disclosed herein. In one embodiment, a stacked microelectronic device assembly can include a first known good packaged microelectronic device including a first interposer substrate. A first die and a first through-casing interconnects are electrically coupled to the first interposer substrate. A first casing at least partially encapsulates the first device such that a portion of each first interconnect is accessible at a top portion of the first casing. A second known good packaged microelectronic device is coupled to the first device in a stacked configuration. The second device can include a second interposer substrate having a plurality of second interposer pads and a second die electrically coupled to the second interposer substrate. The exposed portions of the first interconnects are electrically coupled to corresponding second interposer pads.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/414,864 filed May 1, 2006, now U.S. Pat. No. 7,671,459 which claimsforeign priority benefits of Singapore Application No. 200601271-0 filedFeb. 28, 2006, now Singpore Patent No. 135074, both of which areincorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention is related to microelectronic devices, stackedmicroelectronic devices, and methods for manufacturing such devices.

BACKGROUND

Microelectronic devices generally have a die (i.e., a chip) thatincludes integrated circuitry having a high density of very smallcomponents. In a typical process, a large number of dies aremanufactured on a single wafer using many different processes that maybe repeated at various stages (e.g., implanting, doping,photolithography, chemical vapor deposition, plasma vapor deposition,plating, planarizing, etching, etc.). The dies typically include anarray of very small bond-pads electrically coupled to the integratedcircuitry. The bond-pads are the external electrical contacts on the diethrough which the supply voltage, signals, etc., are transmitted to andfrom the integrated circuitry. The dies are then separated from oneanother (i.e., singulated) by dicing the wafer and backgrinding theindividual dies. After the dies have been singulated, they are typically“packaged” to couple the bond-pads to a larger array of electricalterminals that can be more easily coupled to the various power supplylines, signal lines, and ground lines.

An individual die can be packaged by electrically coupling the bond-padson the die to arrays of pins, ball-pads, or other types of electricalterminals, and then encapsulating the die to protect it fromenvironmental factors (e.g., moisture, particulates, static electricity,and physical impact). In one application, the bond-pads are electricallyconnected to contacts on an interposer substrate that has an array ofball-pads. FIG. 1A schematically illustrates a conventional packagedmicroelectronic device 10 including an interposer substrate 20 and amicroelectronic die 40 attached to the interposer substrate 20. Themicroelectronic die 40 has been encapsulated with a casing 30 to protectthe die 40 from environmental factors.

Electronic products require packaged microelectronic devices to have anextremely high density of components in a very limited space. Forexample, the space available for memory devices, processors, displays,and other microelectronic components is quite limited in cell phones,PDAs, portable computers, and many other products. As such, there is astrong drive to reduce the surface area or “footprint” of themicroelectronic device 10 on a printed circuit board. Reducing the sizeof the microelectronic device 10 is difficult because high performancemicroelectronic devices 10 generally have more bond-pads, which resultin larger ball-grid arrays and thus larger footprints. One techniqueused to increase the density of microelectronic devices 10 within agiven footprint is to stack one microelectronic device 10 on top ofanother.

FIG. 1B schematically illustrates a first packaged microelectronicdevice 10 a attached to a second similar microelectronic device 10 b ina stacked configuration. The interposer substrate 20 of the firstmicroelectronic device 10 a is coupled to the interposer substrate 20 ofthe second microelectronic device 10 b by large solder balls 50. Onedrawback of the stacked devices 10 a-b is that the large solder balls 50required to span the distance between the two interposer substrates 20use valuable space on the interposer substrates 20, which increases thefootprint of the microelectronic devices 10 a-b.

FIG. 2 schematically illustrates another packaged microelectronic device60 in accordance with the prior art. The device 60 includes a firstmicroelectronic die 70 a attached to a substrate 80 and a secondmicroelectronic die 70 b attached to the first die 70 a. The first andsecond dies 70 a-b are electrically coupled to the substrate 80 with aplurality of wire-bonds 90, and the device 60 further includes a casing95 encapsulating the dies 70 a-b and wire-bonds 90. One drawback of thepackaged microelectronic device 60 illustrated in FIG. 2 is that if oneof the dies 70 a-b fails a post-encapsulation quality control test thenthe packaged device 60, including the good die 70, is typicallydiscarded. Similarly, if one of the dies 70 a-b becomes inoperableand/or is damaged after packaging, the entire packaged device 60 (ratherthan just the bad die) is generally discarded. Accordingly, there is aneed to provide stacked microelectronic device packages that have smallfootprints and good dies.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a partially schematic side cross-sectional view of aconventional packaged microelectronic device in accordance with theprior art.

FIG. 1B is a partially schematic side cross-sectional view of thepackaged microelectronic device of FIG. 1A stacked on top of a secondsimilar microelectronic device.

FIG. 2 is a partially schematic side cross-sectional view of anotherpackaged microelectronic device in accordance with the prior art.

FIGS. 3A-7 illustrate stages of a method for manufacturing a pluralityof stacked microelectronic devices in accordance with one embodiment ofthe invention.

FIGS. 8-13 illustrate stages of a method for manufacturing a pluralityof stacked microelectronic devices in accordance with another embodimentof the invention.

FIG. 14 is a partially schematic side cross-sectional view of amicroelectronic device configured in accordance with still anotherembodiment of the invention.

FIGS. 15A-18 illustrate stages of a method for manufacturing a pluralityof stacked microelectronic devices in accordance with yet anotherembodiment of the invention.

FIGS. 19 and 20 illustrate stages of a method for manufacturing aplurality of stacked microelectronic devices in accordance with stillyet another embodiment of the invention.

DETAILED DESCRIPTION A. Overview/Summary

The following disclosure describes several embodiments ofmicroelectronic devices, stacked microelectronic devices, and methodsfor manufacturing such devices. One aspect of the invention is directedtoward a stacked microelectronic device assembly including a first knowngood packaged microelectronic device and a second known good packagedmicroelectronic device coupled to the first device in a stackedconfiguration. The first device can include a first interposer substratewith a plurality of first interposer contacts and a first die carried byand electrically coupled to the first interposer contacts. The firstdevice can also include a first casing having a first face at the firstinterposer substrate and a second face opposite the first face such thatthe first casing encapsulates the first die and at least a portion ofthe first interposer substrate. The first device can further include aplurality of first through-casing interconnects at least partiallyencapsulated in the first casing and in contact with corresponding firstinterposer contacts. The first interconnects extend from the first faceto the second face.

The second device can include a second interposer substrate with aplurality of second interposer pads and a second die carried by andelectrically coupled to the second interposer substrate. The seconddevice can also include a second casing that encapsulates the second dieand at least a portion of the second interposer substrate. The secondinterposer pads are electrically coupled to the exposed portions of thecorresponding first interconnects at the second face of the firstcasing.

The first interconnects can have a number of different configurations.In one embodiment, for example, the first interconnects comprise aplurality of lead fingers attached to the first side of the firstinterposer substrate and projecting inwardly from a periphery of thefirst casing toward the first die. The lead fingers can be in contactwith and electrically coupled to corresponding first interposercontacts. In another embodiment, the first interconnects comprisefilaments attached to and projecting from the first interposer contacts.In still another embodiment, the first interconnects comprise aplurality of openings extending through the first casing and generallyaligned with corresponding first interposer contacts. The individualopenings can be at least partially filled with a conductive material(e.g., a solder material deposited into the openings using a reflowprocess). In some embodiments, the first interconnects are at leastpartially aligned with a periphery of the first casing such that atleast a portion of each interconnect is accessible along the peripheryof the first casing. In other embodiments, however, the firstinterconnects are inboard of the periphery of the first casing such thatthe first interconnects are not accessible along the periphery. Inseveral embodiments, the second device can further include a pluralityof second through-casing interconnects at least partially encapsulatedin the second casing and in contact with corresponding second interposercontacts on the second interposer substrate. The second interconnectscan include features generally similar to the first interconnectsdescribed above. In still further embodiments, one or more additionalknown good packaged microelectronic devices can be attached andelectrically coupled to the second device in a stacked configuration.

Another aspect of the invention is directed toward methods formanufacturing microelectronic devices. One embodiment of such a methodincludes positioning a first known good packaged microelectronic deviceproximate to a second known good packaged microelectronic device. Thefirst device can include a first interposer substrate, a first dieelectrically coupled to the first interposer substrate, and a pluralityof electrically conductive interconnects electrically coupled to theinterposer substrate. The first die, at least a portion of the firstinterposer substrate, and at least a portion of the first interconnectsare encased in a first casing. The first interconnects have accessibleterminals at a top portion of the first casing. The method also includesmounting the second device to the first device in a stackedconfiguration. The second device can include a second interposersubstrate and a second die electrically coupled to the second interposersubstrate. A second casing covers the second die and at least a portionof the second interposer substrate. The terminals of the firstinterconnects at the top portion of the first casing are electricallycoupled to corresponding interposer pads of the second interposersubstrate.

The terms “assembly” and “subassembly” are used throughout to include avariety of articles of manufacture, including, e.g., semiconductorwafers having active components, individual integrated circuit dies,packaged dies, and devices comprising two or more microfeatureworkpieces or components, e.g., a stacked die package. Many specificdetails of certain embodiments of the invention are set forth in thefollowing description and in FIGS. 3A-20 to provide a thoroughunderstanding of these embodiments. A person skilled in the art,however, will understand that the invention may be practiced withoutseveral of these details or additional details can be added to theinvention. Well-known structures and functions have not been shown ordescribed in detail to avoid unnecessarily obscuring the description ofthe embodiments of the invention.

B. Embodiments of Methods for Manufacturing Stacked MicroelectronicDevices and Microelectronic Devices Formed Using Such Methods

FIGS. 3A-7 illustrate stages in a method for manufacturing a pluralityof stacked microelectronic devices in accordance with one embodiment ofthe invention. More specifically, FIG. 3A is a partially schematic, topplan view of a subassembly 100 at an initial stage of the method, andFIG. 3B is a side cross-sectional view taken substantially along line3B-3B of FIG. 3A. Referring to FIGS. 3A and 3B together, the subassembly100 includes a support member 102, such as an interposer substrate, aprinted circuit board, or another suitable structure, and a lead frame120 on the support member. In the illustrated embodiment, the supportmember 102 includes (a) a first side 104 having a plurality of contacts108, (b) a second side 106 opposite the first side 104 and having aplurality of pads 110, and (c) a plurality of traces 112 or other typeof conductive lines between the contacts 108 and corresponding pads 110or other contacts (not shown) at the second side 106 of the supportmember 102. The contacts 108 can be arranged in arrays for electricalconnection to corresponding contacts on the lead frame 120 and/or one ormore microelectronic dies attached to the support member 102, asdescribed in more detail below. In one aspect of this embodiment, thepads 110 at the second side 106 of the support member 102 are arrangedin an array corresponding to a standard JEDEC pinout. In otherembodiments, the support member 102 may include a different number orarrangement of contacts/pads at the first side 104 and/or second side106.

The lead frame 120 is a self-supporting structure that generallyincludes a peripheral dam 122 and a plurality of lead fingers 124projecting inwardly of the peripheral dam 122. The lead fingers 124 arespaced from one another by gaps 126 therebetween. The inner surfaces ofthe peripheral dam 122 and each of the lead fingers 124 together form aninner periphery 128 of an opening 129 in the lead frame 120. In thisexample, the opening 129 extends through the entire thickness of thelead frame 120. The lead frame 120 can be formed of a metal or anothersuitable conductive material. In some embodiments, the lead frame 120can be a conductive material that is plated with a noble metal, such asgold, silver, or palladium, or the lead frame 120 can be anon-conductive material coated with a conductive material. A portion ofeach lead finger 124 contacts a corresponding contact 108 on the supportmember 102.

Although six lead fingers 124 are shown in the illustrated embodiment,the lead frame 120 can have a different number of lead fingers 124based, at least in part, on the configuration of the microelectronic diethat is to be electrically coupled to the lead frame 120. In still otherembodiments, the lead fingers 124 can include more complex shapesinstead of the fairly simple, block-shaped lead fingers 124 shown in theillustrated embodiment.

In one aspect of this embodiment, the peripheral dam 122 and each of thelead fingers 124 have generally the same height D₁. As described in moredetail below, the height D₁ should be greater than the height of amicroelectronic die to be positioned on the support member 102. In otherembodiments, however, the height of the lead fingers 124 may bedifferent than the height of the peripheral dam 122.

Referring next to FIGS. 4A and 4B, a microelectronic die 140 may bepositioned within the opening 129 of the lead frame 120. Although only asingle lead frame 120 and die 140 are shown attached to the supportmember 102, a plurality of lead frames 120 and dies 140 can be attachedto the support member 102 for manufacturing a plurality ofmicroelectronic devices. The die 140 can include a front or active side142, a back side 144 opposite the active side 142, and integratedcircuitry 146 (shown schematically). The back side 144 of the die 140 isattached to the exposed first side 104 of the support member 102 withinthe opening 129. The die 140 can also include a plurality of terminals148 (e.g., bond-pads) arranged in an array at the active side 142 andelectrically coupled to the integrated circuitry 146. The terminals 148accordingly provide external contacts to provide source voltages, groundvoltages, and signals to the integrated circuitry 146 in the die 140. Inthe illustrated embodiment, the terminals 148 are adjacent to theperiphery of the die 140 and electrically coupled to correspondingcontacts 108 on the support member 102 by wire-bonds 150 or other typesof connectors. The wire-bonds 150 generally include a loop height thatremains below the height D₁ of the lead frame 120 to ensure completeencapsulation of the wire-bonds 150 by an encapsulant, as described inmore detail below.

In other embodiments, the die 140 can have other features and/or the diecan be attached and electrically coupled to the support member 102 usingother arrangements, such as a flip-chip configuration (FCIP) or anothersuitable method. Furthermore, the order in which the lead frame 120 anddie 140 are attached to the support member 102 can be varied. In theembodiment described above, the lead frame 120 is attached to thesupport member 102 before the die 140 is attached to the support member.In other embodiments, however, the die 140 can be attached to thesupport member 102 before the lead frame 120 is attached to the supportmember. In still further embodiments, the lead frame 120 and the die 140may be simultaneously attached to the support member 102.

Referring next to FIGS. 5A and 5B, an encapsulant 160 may be disposed inthe opening 129 after the die 140 is electrically coupled to thecontacts 108 to form a casing 162 that encapsulates at least a portionof the subassembly 100. More particularly, the exposed first side 104 ofthe support member 102, the inner periphery 128 of the lead frame 120,and the die 140 define a cavity 152 within the opening 129 that may bepartially or completely filled with the encapsulant 160 to form thecasing 162. In the illustrated embodiment, the cavity 152 is completelyfilled with the encapsulant 160 such that an upper portion 164 of thecasing 162 is substantially coplanar with an upper portion 130 of thelead fingers 124. In other embodiments, however, the upper portion 164of the casing 162 may be below the upper portion 130 of the lead fingers124 as long as the die 140 and corresponding wire-bonds 150 arecompletely encapsulated.

The encapsulant 160 can be deposited into the opening 129 using asuitable application process, such as conventional injection molding,film molding, or other suitable process. In several embodiments, theencapsulant 160 is delivered to the cavity 152 and is allowed to simplyfill the cavity and cover the die 140 and wire-bonds 150. If anyencapsulant 160 flows outwardly over the upper portion 130 of the leadfingers 124, the overburden of encapsulant material can be removed bygrinding, polishing, or other suitable techniques. In other embodiments,however, the flow of encapsulant 160 can be limited by use of a moldingelement (not shown) having a substantially flat molding surface thatlies substantially flush against the upper portion 130 of the leadfingers 124 to keep the encapsulant 160 from flowing over the lead frame120.

As best seen in FIG. 5A, the peripheral dam 122 physically connects eachof the lead fingers 124 to each other and helps define the cavity 152for receiving the encapsulant 160 as described above. Once the casing162 is in place, however, the peripheral dam 122 is no longer needed.Accordingly, the subassembly 100 can be cut along lines A-A to removethe peripheral dam 122 and form a packaged microelectronic device 170(FIGS. 6A and 6B) having a plurality of isolated lead fingers 124 spacedabout a periphery of the device 170. The subassembly 100 can be cutusing a conventional wafer saw, high-pressure water jets, lasers, or thelike. In other embodiments, the lines A-A can be moved slightly inwardtoward the die 140 such that a portion of each lead finger 124 is alsoremoved along with the peripheral dam 122.

Referring next to FIGS. 6A and 6B, the device 170 can be testedpost-packaging to ensure that the device functions properly so that onlyknown good devices undergo further processing. Furthermore, a pluralityof electrical couplers 166 (e.g., solder balls) can be attached tocorresponding pads 110 at the second side 106 of the support member 102.The electrical couplers 166 are generally attached to the device 170after testing to ensure that the couplers are only attached to knowngood devices, but in some embodiments the couplers can be attached tothe device before testing.

One feature of the device 170 is that the upper portion 164 of thecasing 162 is substantially coplanar with the upper portion 130 of thelead fingers 124. The device 170 is accordingly a mechanically stablestructure wherein each of the lead fingers 124 defines an electricalpathway between the pads 110 at the second side 106 of the supportmember 102 and the upper portion 130 of corresponding lead fingers 124.As explained below, this feature can facilitate stacking of two or moredevices 170. Another feature of the device 170 is that at least aportion of each lead finger 124 is accessible along a periphery of thecasing 162. More specifically, each lead finger 124 includes a frontsurface 132 facing toward the die 140 and a back surface 134 oppositethe front surface 132 and generally aligned with the periphery of thecasing 162. One advantage of this feature is that the accessible backsurface 134 of each lead finger 124 can provide additional contactpoints to facilitate testing of the device 170.

FIG. 7 is a side cross-sectional view of a stacked microelectronicdevice assembly 190 including an upper microelectronic device 170 astacked on top of a lower microelectronic device 170 b. The upper andlower devices 170 a and 170 b can be generally similar to themicroelectronic device 170 described above with respect to FIGS. 6A and6B. The upper device 170 a differs from the device 170 described above,however, in that the device 170 a includes an array of pads 111 a at thesecond side 106 of the support member 102 having a different arrangementthan the array of pads 110 of the device 170. More specifically, thedevice 170 a is configured to be an “upper” device in a stacked assemblyand, accordingly, the pads 111 a are arranged such that they contactcorresponding lead fingers 124 of the lower device 170 b to electricallycouple the upper device 170 a and lower device 170 b together.Furthermore, the upper device 170 a does not generally includeelectrical couplers attached to the pads 111 a. In other embodiments,the upper device 170 a and/or lower device 170 b can have differentarrangements. For example, the upper device 170 a can include aplurality of pads 110 a (shown in broken lines) having an arrangementgenerally similar to the arrangement of pads 110 of the device 170described above. The lead fingers 124 of the lower device 170 b caninclude engagement portions 124 a (shown in broken lines) projectingfrom the front surface 132 of each lead finger 124 and configured tocontact corresponding pads 110 a. In still other embodiments, the upperand lower device 170 a and 170 b can include other features.

The upper device 170 a is coupled to the lower device 170 b by attachingand electrically coupling the pads 111 a of the upper device 170 a tocorresponding lead fingers 124 on the lower device 170 b. In theillustrated embodiment, the second side 106 of the upper device'ssupport member 102 is in direct contact with the upper portion 164 ofthe lower device's casing 162. Accordingly, the stacked assembly 190does not include a fill material between the upper and lower devices 170a and 170 b. As mentioned previously, however, in other embodiments theupper portion 164 of the casing 162 may not be coplanar with the upperportion 130 of the lead fingers 124 and, accordingly, a fill material(not shown) may be deposited into a gap or cavity between the upperdevice 170 a and the lower device 170 b. The fill material (e.g., anepoxy resin or other suitable molding compound) can enhance theintegrity of the stacked assembly 190 and protect the components of theupper device and the lower device from moisture, chemicals, and othercontaminants. The fill material, however, is an optional component.

One advantage of the devices 170 formed using the methods describedabove with reference to FIGS. 3A-7 is that the devices can be stacked ontop of each other. Stacking microelectronic devices increases thecapacity and/or performance within a given surface area or footprint.For example, when the upper microelectronic device 170 a is stacked ontop of the lower microelectronic device 170 b and the lower device 170 bis attached to a circuit board or other external device, the uppermicroelectronic device 170 a is electrically and operably coupled to thecircuit board or external device without using any more surface area onthe circuit board.

One feature of the stacked assembly 190 is that both the upper and lowerdevices 170 a and 170 b can be tested after packaging and beforestacking to ensure that they function properly before being assembledtogether. Throughput of stacked assemblies 190 can accordingly beincreased because defective devices can be detected and excluded fromthe stacked assemblies 190 formed using the methods described above andeach assembly will generally include only known good devices. Thisincreases the yield of the packaging processes described above andreduces the number of devices that malfunction and/or include defects.

Still another feature of the devices 170 described above with referenceto FIGS. 3A-7 is that the electrical couplers 166 are positioned inboardof the lead fingers 124. An advantage of this feature is that thefootprint of the stacked assembly 190 is reduced as compared withconventional stacked devices, such as the devices 10 a and 10 billustrated in FIG. 1B where the solder balls 50 are outboard of thedies 40. Minimizing the footprint of microelectronic devices isparticularly important in cell phones, PDAs, and other electronicproducts where there is a constant drive to reduce the size ofmicroelectronic components used in such devices.

C. Additional Embodiments of Methods for Manufacturing StackedMicroelectronic Devices and Microelectronic Devices Formed Using SuchMethods

FIGS. 8-21 illustrate various stages in other embodiments of methods formanufacturing stacked microelectronic devices. The following methods anddevices formed using such methods can have many of the same advantagesas the devices 170 and the stacked assembly 190 described above withrespect to FIGS. 3A-7.

FIG. 8, for example, is a schematic side cross-sectional view of asubassembly 200 including a plurality of microelectronic dies 220 (onlythree are shown) arranged in an array on a support member 202. Thesupport member 202 can include an interposer substrate, a printedcircuit board, or other suitable support member for carrying the dies220. In the illustrated embodiment, the support member 202 includes (a)a first side 204 having a plurality of contacts 208, and (b) a secondside 206 having a plurality of first pads 210 and a plurality of secondpads 212. The contacts 208 can be arranged in arrays for electricalconnection to corresponding terminals on the dies 220 and the first andsecond pads 210 and 212 can be arranged in arrays to receive a pluralityof electrical couplers (e.g., solder balls) and/or other types ofelectrical interconnects. The support member 202 further includes aplurality of conductive traces 214 electrically coupling the contacts208 to corresponding first and second pads 210 and 212. In one aspect ofthis embodiment, the first and/or second pads 210 and 212 at the secondside 206 of the support member 202 are arranged in an arraycorresponding to a standard JEDEC pinout. In other embodiments, thesupport member 202 may include a different number or arrangement ofcontacts/pads at the first side 204 and/or the second side 206.

The individual dies 220 include integrated circuitry 222 (shownschematically), a front or active side 224, a plurality of terminals 226(e.g., bond-pads) arranged in an array at the active side 224 andelectrically coupled to the integrated circuitry 222, and a back side228 opposite the active side 224. The back sides 228 of the dies 220 areattached to the support member 202 with an adhesive 230, such as anadhesive film, epoxy, tape, paste, or other suitable material. Aplurality of wire-bonds 232 or other types of connectors couple theterminals 226 on the dies 220 to corresponding contacts 208 on thesupport member 202. Although the illustrated dies 220 have the samestructure, in other embodiments, the dies 220 may have differentfeatures to perform different functions. In further embodiments, thedies 220 may be attached and electrically coupled to the support member202 using other arrangements, such as an FCIP configuration or anothersuitable method.

FIG. 9 is a schematic side cross-sectional view of the subassembly 200after attaching a plurality of interconnects or filaments 234 to thecontacts 208 at the first side 204 of the support member 202. Theinterconnects or filaments 234 can include thin, flexible wires attachedand electrically coupled to corresponding contacts 208. In theillustrated embodiment, for example, the interconnects 234 includerelatively straight, free-standing wire-bond lines that are attached toand project away from the contacts 208 in a direction generally normalto the first side 204 of the support member 202. The interconnects 234include a height H relative to the first side 204 of the support member202 that is based, at least in part, on the desired height of theresulting packaged device. The interconnects 234 can also include anelectrical coupler 236 (e.g., a ball-shaped portion) at a distal end ofeach interconnect. As described in more detail below, the electricalcouplers 236 can help improve joint interconnection with one or moredevices that may be stacked on the dies 220. The interconnects 234 aregenerally attached to the contacts 208 after forming the wire-bonds 232,but in some embodiments the interconnects 234 and wire-bonds 232 can beformed at the same time. In other embodiments, such as the embodimentdescribed below with respect to FIG. 15, the interconnects 234 can havea different arrangement and/or include different features.

Referring to FIG. 10, an encapsulant 240 is deposited onto the supportmember 202 to form a plurality of casings 242 encapsulating the dies220, the wire-bonds 232, and at least a portion of the interconnects234. The encapsulant 240 can be deposited onto the support member 202using a suitable application process, such as conventional injectionmolding, film molding, or other suitable process.

Referring next to FIG. 11, a top portion 244 (shown in broken lines) ofthe casings 242 can be removed to at least partially expose theelectrical couplers 236 at the distal end of the interconnects 234. Thetop portion 244 of the casings 242 can be removed using a laser grindingprocess or another suitable process. In other embodiments, a mold usedduring encapsulation of the subassembly 200 can include cavities orrecesses corresponding to the arrangement of electrical couplers 236such that the individual electrical couplers are not encapsulated whenforming the casings 242 and, therefore, a grinding or removal process isnot necessary. In still other embodiments, the encapsulant 240 can bedeposited using another suitable process that leaves the electricalcouplers 236 exposed after the device is removed from the mold. In stillfurther embodiments, a laser drilling process can be used afterencapsulation to isolate and expose at least a portion of theinterconnects 234 and a conductive material (e.g., gold) can bedeposited into the resulting vias to create a plurality of conductivepads in a desired arrangement at the top portion 244 of the casing 242.If desired, a redistribution structure can then be formed at the topportion 244 to redistribute the signals from the conductive pads to alarger array of contacts. After at least partially exposing theelectrical couplers 236 of the interconnects 234, the subassembly 200can be cut along lines B-B to singulate a plurality of individualmicroelectronic devices 250.

Referring next to FIG. 12, the individual devices 250 can be testedpost-packaging to ensure that each device functions properly so thatonly known good devices undergo further processing. Further, a pluralityof electrical couplers 252 (e.g., solder balls) can be attached tocorresponding pads 212 at the second side 206 of the support member 202.The electrical couplers 252 are generally attached to the devices 250after testing to ensure that the couplers are only attached to knowngood devices, but in some embodiments the couplers can be attached tothe devices before testing.

In several embodiments, one or more individual devices 250 can bestacked together to form stacked microelectronic device assemblies. FIG.13, for example, is a side cross-sectional view of a stackedmicroelectronic device assembly 290 including an upper microelectronicdevice 250 a stacked on top of a lower microelectronic device 250 b. Theupper and lower devices 250 a and 250 b can be generally similar to thedevices 250 described above with respect to FIGS. 8-12. The upper device250 a can be coupled to the lower device 250 b by attaching the secondside 206 of the upper device's support member 202 to the top portion 244of the lower device's casing 242 with an adhesive material 260, such asan adhesive film, epoxy, tape, paste, or other suitable material. Thelower device's electrical couplers 236 b can be electrically coupled tocorresponding first pads 210 a on the upper device 250 a. In theillustrated embodiment, for example, each of the electrical couplers 236b is electrically coupled to corresponding first pads 210 a withelectrical connectors 262. The electrical connectors 262 may alsophysically bond (at least in part) the upper device 250 a to the lowerdevice 250 b. The electrical connectors 262 can include solderconnections that are reflowed as is known in the art or other suitableconnectors.

In several embodiments, a fill material 264 can be deposited into thearea between the upper device 250 a and the lower device 250 b and, ifno additional devices are to be stacked on the upper device 250 a, overthe exposed electrical couplers 236 a at the top portion 244 of theupper device 250 a. The fill material 264 can enhance the integrity ofthe stacked assembly 290 and protect the components of the upper andlower devices 250 a and 250 b from moisture, chemicals, and othercontaminants. In one embodiment, the fill material 264 can include amolding compound such as an epoxy resin. In other embodiments, the fillmaterial 264 can include other suitable materials. Depositing the fillmaterial 264 is an optional step that may not be included in someembodiments.

In other embodiments, additional microelectronic devices can be stackedonto the upper microelectronic device 250 a by exposing the electricalcouplers 236 a at the top portion 244 of the upper device 250 a,stacking one or more additional devices (not shown) onto the upperdevice 250 a, and electrically coupling the additional devices to theelectrical couplers 236 a. In still further embodiments, the upper andlower devices 250 a and 250 b can be different devices. For example, themicroelectronic dies 220 in the upper and lower devices 250 a and 250 bcan be the same or different types of dies and/or the upper and lowerdevices 250 a and 250 b can include other features.

FIG. 14 illustrates a microelectronic device 350 configured inaccordance with another embodiment of the invention. The microelectronicdevice 350 is generally similar to the microelectronic devices 250described above with reference to FIGS. 8-12. Accordingly, likereference numbers are used to refer to like components in FIGS. 8-12 andFIG. 14. The device 350 differs from the device 250, however, in thatthe device 350 includes a interconnect 334 having a differentconfiguration than the interconnect 234 of the device 250. Morespecifically, the interconnect 334 of the device 350 includes a wireloop such that a ball portion and a stitch portion of the wire are bothat the corresponding contacts 208 on the support member 202. Theloop-shaped interconnect can have the height H generally similar to theinterconnect 234 described above such that a top portion 335 of theinterconnect 334 can be exposed at the top portion 244 of the casing242. One advantage of the loop-shaped interconnects 334 is that suchinterconnects are generally expected to be more durable than thesingle-filament interconnects 234 described previously because theloop-shaped interconnects are more securely anchored to thecorresponding contacts 208 and, accordingly, are less likely to bend ordisconnect from the contacts during molding. Furthermore, in severalembodiments the loop-shaped interconnects 334 can provide lowerinductance than the interconnects 234.

FIGS. 15A-18 illustrate stages in yet another embodiment of a method formanufacturing a plurality of stacked microelectronic devices. FIG. 15A,for example, is a partially schematic, isometric view of a subassembly400 at an initial stage of the method. The subassembly 400 includes aplurality of microelectronic dies 430 (shown in broken lines) arrangedin an array on a support member 402 and encapsulated with a casing 462.It will be appreciated that although only four dies 430 are shownattached to the support member 402 in the illustrated embodiment, adifferent number of dies 430 can be attached to the support member 402for manufacturing a plurality of microelectronic devices. Thesubassembly 400 further includes a plurality of small openings or vias440 (i.e., “pin holes”) extending through the casing 462 to a first side404 of the support member 402. The openings 440 are generally arrangedin the “streets” or non-active areas between the individual dies 430.The openings 440 are discussed in greater detail below with reference toFIGS. 16A and 16B.

FIG. 15B is a side cross-sectional view taken substantially along lines15B-15B of FIG. 15A. Referring to FIGS. 15A and 15B together, thesupport member 402 can include an interposer substrate, a printedcircuit board, or other suitable support member. In the illustratedembodiment, the support member 402 includes (a) the first side 404having a plurality of first contacts 408 and a plurality of secondcontacts 409, (b) a second side 406 opposite the first side 404 andhaving a plurality of first pads 410 and a plurality of second pads 411,and (c) a plurality of traces 412 or other type of conductive linesbetween the first and/or second contacts 408 and 409 and correspondingfirst and/or second pads 410 and 411 or other contacts (not shown) atthe second side 406 of the support member 402. The first and secondcontacts 408 and 409 can be arranged in arrays for electrical connectionto corresponding contacts on the dies 430 and one or more devicesstacked on the packaged dies, as described in more detail below. In oneaspect of this embodiment, the second pads 411 at the second side 406 ofthe support member 402 are arranged in an array corresponding to astandard JEDEC pinout. In other embodiments, the support member 402 mayinclude a different number or arrangement of contacts and/or pads.

The individual microelectronic dies 430 can include a front or activeside 432, a back side 434 opposite the active side 432, and integratedcircuitry 436 (shown schematically). The back side 434 of the dies 430can be attached to the first side 404 of the support member 402 with anadhesive (not shown). The dies 430 can also include a plurality ofterminals 438 (e.g., bond-pads) arranged in an array at the active side432 and electrically coupled to the integrated circuitry 436. In theillustrated embodiment, the terminals 438 are arranged adjacent aperiphery of the dies 430 and used to electrically couple the dies 430to the support member 402 using a chip-on-board (COB) configuration.More specifically, a plurality of wire-bonds 439 or other types ofconnectors extend between the terminals 438 and corresponding secondcontacts 409 on the support member 402. In other embodiments, the dies430 can have other features and/or the dies can be attached andelectrically coupled to the support member 402 using other arrangements,such as an FCIP configuration, a board-on-chip (BOC) configuration, oranother suitable configuration.

Referring next to FIGS. 16A and 16B, a conductive material 442 isdeposited into each of the openings 440 to form a plurality ofelectrically conductive interconnects 444 extending through the casing462 to corresponding first contacts 408 on the support member 402. Inone embodiment, for example, a solder ball (not shown) is placed at atop portion of each opening 440 and reflowed such that the soldergenerally fills the corresponding opening. In other embodiments,however, the conductive material 442 can be deposited into the openings440 using other suitable methods. After forming the conductiveinterconnects 444, the subassembly 400 can be cut along lines C-C tosingulate a plurality of individual microelectronic devices 450.

FIG. 17A, for example, is a partially schematic, isometric view of asingulated device 450, and FIG. 17B is a side cross-sectional view takensubstantially along lines 17B-17B of FIG. 17A. Referring to FIGS. 17Aand 17B together, the individual devices 450 can be tested at this stageof the method to ensure that each device functions properly so that onlyknown good devices undergo further processing. The device 450illustrated in FIGS. 17A and 17B is configured to be a “bottom” or“lower” device in a stacked microelectronic device and, accordingly, aplurality of electrical couplers (not shown) can be attached tocorresponding second pads 411 at the second side of the support member402. As discussed previously, the second pads 411 are arranged to have astandard JEDEC pinout. On the other hand, if the device 450 wasconfigured to be an “upper” device (i.e., a device stacked on one ormore lower devices), the second pads 411 could have a differentarrangement and/or electrical couplers may not be attached to the secondpads.

One feature of the device 450 is that the interconnects 444 are at leastpartially exposed at a top portion 454 and a periphery portion 452 ofthe device 450. The exposed interconnects 444 accordingly define anelectrical pathway between the first and second pads 410 and 411 at thesecond side 406 of the support member 402 and the top portion 454 of thedevice 450. As explained below, this feature can facilitate stacking oftwo or more devices 450.

FIG. 18, for example, is a partially schematic, isometric view of astacked microelectronic device assembly 490 including a firstmicroelectronic device 450 a, a second upper microelectronic device 450b stacked on the first microelectronic device 450 a, and a thirdmicroelectronic device 450 c on the second microelectronic device 450 b.The devices 450 a-c can be generally similar to the devices 450described above with respect to FIGS. 15A-17B. The second device 450 bcan be coupled to the first device 450 a by attaching the first pads 410b at the second side 406 of the second device's support member 402 tocorresponding exposed portions of the first device's interconnects 444at the top portion 454 of the first device 450 a. The third device 450 ccan be coupled to the second device 450 b in a generally similar manner.

In one embodiment, a plurality of extremely small alignment holes (notshown) can be formed completely through each device 450 a-c beforestacking the devices together. Either during or after stacking thedevices 450 together, a laser beam or other suitable beam of light canbe directed through the alignment holes in the stacked assembly 490 toensure that the individual devices are properly aligned relative to eachother so that the external electrical contacts on each device are incontact with appropriate contacts on the adjoining device(s). Forexample, if the beam passes completely through the stacked assembly, thealignment holes in each device are properly aligned. On the other hand,if the light does not pass completely through the stacked assembly, oneor more of the devices are out of alignment. In other embodiments, othersuitable methods can be used to align the individual devices 450relative to each other in the stacked assembly 490.

FIGS. 19 and 20 illustrate stages of a method for manufacturing aplurality of stacked microelectronic devices in accordance with stillyet another embodiment of the invention. This method can include severalsteps that are at least generally similar to those described above withrespect to FIGS. 15A-17B. FIG. 19, for example, is a sidecross-sectional view of a microelectronic device 550 having a number offeatures generally similar to the devices 450 described above withreference to FIGS. 15A-17B. The arrangement of the die and theconfiguration of the interconnects in the device 550, however, differfrom the arrangement of the die 430 and the interconnects 444 in thedevices 450. More specifically, the device 550 includes a die 530 havinga FCIP configuration rather than the COB configuration of the die 430 inthe devices 450 described above. Moreover, the device 550 includes aplurality of interconnects 544 positioned inboard of a periphery portion554 of the device 550, in contrast with the interconnects 444 that areat least partially exposed about the periphery portion 452 of thedevices 450.

The die 530 of the device 550 can include an active side 532 attached tothe first side 404 of the support member 402, a back side 534 oppositethe active side 532, and integrated circuitry 536 (shown schematically).The die 530 can also include a plurality of terminals 538 electricallycoupled to the integrated circuitry 536 and attached to correspondingfirst contacts 508 at the first side 404 of the support member 402. Thefirst contacts 508 can have a different arrangement on the supportmember 402 than the arrangement of first contacts 408 describedpreviously. In other embodiments, the die 530 can include differentfeatures and/or can be attached to the support member 402 using adifferent arrangement.

The interconnects 544 extend through the casing 462 to correspondingsecond contacts 509 on the support member 402. The interconnects 544 canbe formed using methods generally similar to those used to form theinterconnects 444 described above. One particular aspect of theinterconnects 544 in the illustrated embodiment is that theinterconnects are arranged in laterally adjacent pairs (shown as a firstinterconnect 544 a and a second interconnect 544 b) about the die 530.One advantage of this feature is that it increases the number of signalsthat can be passed from the device 550 to an external device withoutsubstantially increasing the footprint of the device 550. In otherembodiments, the interconnects 544 can have different arrangements aboutthe die (e.g., single interconnects arranged inboard of the periphery ofthe device 550 or more than two interconnects arranged together).

The device 550 also includes a plurality of first pads 510 and aplurality of second pads 511 at the second side 406 of the supportmember 402. The first pads 510 are arranged in an array corresponding toa standard JEDEC pinout and the second pads 511 are arranged in apattern generally corresponding to the arrangement of the secondcontacts 509 at the first side 404 of the support member 402 tofacilitate stacking of two more devices 550. In several embodiments, aplurality of electrical couplers 566 (e.g., solder balls) can beattached to corresponding first pads 510.

FIG. 20, for example, is a side cross-sectional view of a stackedmicroelectronic device assembly 590 including an upper microelectronicdevice 550 a stacked on top of a lower microelectronic device 550 b. Theupper and lower devices 550 a and 550 b can be generally similar to themicroelectronic device 550 described above with respect to FIG. 19. Theupper device 550 a differs from the device 550 described above, however,in that the device 550 a is configured to be an “upper” device in astacked assembly and, accordingly, the upper device 550 a generally doesnot include electrical couplers attached to the first pads 510 a.

The upper device 550 a is coupled to the lower device 550 b by attachingand electrically coupling the second pads 511 of the upper device 550 ato corresponding interconnects 544 on the lower device 550 b. In theillustrated embodiment, for example, the second side 406 of the upperdevice's support member 402 is in direct contact with the top portion ofthe lower device's casing. In other embodiments, however, a plurality ofelectrical couplers (not shown) may be used to couple the upper device'ssecond pads 511 to corresponding interconnects 544 on the lower device550 b. In embodiments including electrical couplers, a filler material(not shown) may also be deposited into the resulting gap between theupper device 550 a and the lower device 550 b.

One feature of the stacked assemblies 190/290/490/590 described abovewith respect to FIGS. 7, 13, 18, and 20, respectively, is that theindividual microelectronic devices 170/250/450/550 in each assemblyinclude through-packaging interconnects that are at least partiallyexposed at a top portion of each device's casing to facilitate stackingof the individual devices without requiring intermediate structures orlarge solder balls between the stacked devices. An advantage of thisfeature is that it can reduce the vertical profiles of the stackedassemblies 190/290/490/590. Devices with smaller vertical profiles areextremely desirable in cell phones, PDAs, and other electronic deviceswhere there is a constant drive to reduce the size of microelectroniccomponents used in such devices.

From the foregoing, it will be appreciated that specific embodiments ofthe invention have been described herein for purposes of illustration,but that various modifications may be made without deviating from theinvention. For example, one or more additional microelectronic devicesmay be stacked on the devices in each of the embodiments described aboveto form stacked devices including a greater number of stacked units.Furthermore, one or more additional microelectronic dies may be stackedon the dies in each of the microelectronic devices described above toform individual microelectronic devices having more than one die. Themicroelectronic devices may also include a number of other differentfeatures and/or arrangements. Aspects of the invention described in thecontext of particular embodiments may be combined or eliminated in otherembodiments. Further, although advantages associated with certainembodiments of the invention have been described in the context of thoseembodiments, other embodiments may also exhibit such advantages, and notall embodiments need necessarily exhibit such advantages to fall withinthe scope of the invention. Accordingly, the invention is not limitedexcept as by the appended claims.

We claim:
 1. A stacked microelectronic device assembly, comprising: afirst known good packaged microelectronic device including— a firstinterposer substrate with a plurality of first interposer contacts; afirst die carried by the first interposer substrate and electricallycoupled to the first interposer contacts via a plurality of wire-bonds;a first casing having a first face at the first interposer substrate anda second face opposite the first face, wherein the first casingcompletely encapsulates the first die and at least a portion of thefirst interposer substrate; and a plurality of first through-casinginterconnects at least partially encapsulated in the first casing andextending from the first face to the second face, wherein the firstinterconnects comprise filaments attached to and projecting away fromcorresponding first interposer contacts, and wherein the filamentscomprise thin, flexible wires, wherein each of the plurality ofwire-bonds physically contacts one of the plurality of firstthrough-casing interconnects; and a second known good packagedmicroelectronic device coupled to the first device in a stackedconfiguration, the second device including— a second interposersubstrate with a plurality of second interposer pads; a second diecarried by the second interposer substrate and electrically coupled tothe second interposer pads; and a second casing completely encapsulatingthe second die and at least a portion of the second interposersubstrate, wherein the second interposer pads are in direct contact withand electrically coupled to exposed portions of the corresponding firstinterconnects at the second face of the first casing.
 2. The stackedmicroelectronic device assembly of claim 1 wherein the filamentscomprise first filaments, and wherein: the first interposer substrateincludes a first side and a second side opposite the first side, thefirst interposer contacts being arranged in a desired pattern at thefirst side; the second interposer substrate includes a first side, asecond side opposite the first side, a plurality of second interposercontacts arranged in a desired pattern at the first side, and the secondinterposer pads arranged in a desired pattern at the second side; andthe assembly further comprises a plurality of second filaments attachedto and projecting away from corresponding second interposer contacts. 3.The stacked microelectronic device assembly of claim 2 wherein: thefirst filaments include a plurality of first free-standing wire-bondlines attached to corresponding first interposer contacts; and thesecond filaments include a plurality of second free-standing wire-bondlines attached to corresponding second interposer contacts.
 4. Thestacked microelectronic device assembly of claim 2 wherein: the firstfilaments include a plurality of first wire loops attached tocorresponding first interposer contacts; and the second filamentsinclude a plurality of second wire loops attached to correspondingsecond interposer contacts.
 5. The stacked microelectronic deviceassembly of claim 1 wherein the wire-bonds comprise first wire-bonds,and wherein: the first interposer substrate includes a first side and asecond side opposite the first side, the first interposer contacts beingarranged in a desired pattern at the first side; the first die iselectrically coupled to corresponding first interposer contacts with thefirst wire-bonds; the second interposer substrate includes a first side,a second side opposite the first side, a plurality of the secondinterposer contacts arranged in a desired pattern at the first side, andthe second interposer pads arranged in a desired pattern at the secondside; and the second die is electrically coupled to corresponding secondinterposer contacts with a plurality of second wire-bonds.
 6. Thestacked microelectronic device assembly of claim 1 wherein the firstinterposer substrate includes a first side, a second side opposite thefirst side, the first interposer contacts arranged in a desired patternat the first side, and a plurality of first interposer pads at thesecond side arranged in a pattern corresponding to a standard JEDECpinout.
 7. The stacked microelectronic device assembly of claim 6,further comprising a plurality of electrical couplers attached tocorresponding first interposer pads.
 8. The stacked microelectronicdevice assembly of claim 1 wherein: the second interposer substrateincludes a first side, a second side opposite the first side, aplurality of the second interposer contacts arranged in a desiredpattern at the first side, and the second interposer pads arranged in adesired pattern at the second side; the second casing has a first faceat the first side of the second interposer substrate and a second faceopposite the first face; the second device further comprises a pluralityof second through-casing interconnects at least partially encapsulatedin the second casing, wherein the second interconnects comprise secondfilaments attached to and projecting away from corresponding secondinterposer contacts, and wherein the second interconnects extend fromthe first face of the second casing to the second face of the secondcasing; and the assembly further comprises a third known good packagedmicroelectronic device coupled to the second device in a stackedconfiguration, the third device including (a) a third interposersubstrate with a plurality of third interposer pads, (b) a third diecarried by and electrically coupled to the third interposer substrate,and (c) a third casing that encapsulates the third die and at least aportion of the third interposer substrate, wherein the third interposerpads are electrically coupled to the exposed portions of thecorresponding second interconnects at the second face of the secondcasing.